What's New in Accessibility

Discover what's new in accessibility in iOS, watchOS, macOS, and tvOS. Learn how to audit an App for accessibility, and take advantage of new assistive features. Topics include how to best customize how Voice Over describes an App UI to the user, how to enhance the accessibility user experience with new features like Drag and Drop, and how to take advantage of sophisticated accessibility APIs to solve common issues.

WWDC 2017

Good afternoon everyone.
I hope everybody's having a
great WWDC so far and that some
of you managed to go see Todd's
talk just a little bit ago, he's
a great speaker and an
all-around awesome dude, so I
hope you enjoyed that.

My name is Skylar Peterson, I am
a member of Apple's iOS
Accessibility Team and I'm here
today to talk to you about
what's new in accessibility this
year.

So, for those of you that don't
know exactly what I mean when I
say accessibility well first of
all, I'm happy that you're here
and second, when we think about
Accessibility it's really making
technology usable by everyone
regardless of whatever their
unique needs might be.

At Apple, we approach this
problem by examining four major
classes of user ability,
cognitive, motor, vision and
hearing.
Cognitive encompasses conditions
like dyslexia or autism.
Motor examines the way in which
a user physically interacts with
the system, whether they need
special accommodations for a
condition like Parkinson's or
cerebral palsy.
Vision which encompasses a range
of visionability from those with
low vision conditions to those
who are completely blind.
And finally hearing which like
vision encompasses a spectrum of
hearing ability from those who
are hard of hearing to those
that are completely deaf.
Worldwide there are over a
billion people who have some
form of disability that fit into
one of those categories.
Put another way, one in seven,
one in seven people have a form
of disability which means that
you're going to have and already
do have users that have a
disability.
But at the end of the day
accessibility isn't about
numbers it's about people.
Accessibility is about the way
in which people interact with
the world.
It's about technology's
transformative power to enable.
It's about expanding the
possibilities of what people can
do.
Accessibility is full of
incredible stories, stories like
Todd's.
In fact, we availed a video
series highlighting some of
these stories and I'd like to
share one of them with you now.
Now, are you going to be able
to play today or not, Morgan?
All right, guys.
Ready to try it?
Let's try it.
Clarinets, you up?
Clarinets ready?
I love seeing the I got it face
when they understand and get
something, you can actually see
it in their faces and that
encourages me to do more.
Clean music joke.
Howard, go.
We tend to joke around the
classroom, I think that's part
of teaching let them see that
you're human.

I said a joke not two words, sit
down.
No, it's a joke.

That was not the best, was
it?
For homework, the students they
record themselves playing.
I can stream the music from the
iPad into my hearing aids and
actually it sounds like they're
right next to me, so I can grade
it right then and there.
Band is a family.

Once you walk in these doors it
doesn't matter where you come
from you're accepted.
And that'll be a dramatic pause
there.
So, we've gone about tackling
problems that people like Shane
face every day by creating a
wide array of baked in
system-level features across all
of our platforms.

Which includes making sure that
our software works well with an
assortment of hardware
accessories made specifically
for people with disabilities.
But at the end of the day what
really makes Apple's platforms
great is the work that people
like you do every day to make
sure that all of those amazing
bits of content that you work on
work for everyone.

So, with that in mind, let's
take a look at what we're going
to talk about today.

The first thing I'd like to do
is highlight some of our new
assistive features across all of
our platforms.
And from there I'd like to shift
to talking about what you as a
developer can do to make sure
that your stuff works with our
stuff.

And that really starts by
auditing your own app for
accessibility, looking at what
the current accessibility
experience is like.
And from there we're going to
take a look at some of the
basics of our accessibility API
and the way that you can take
advantage of it to solve some of
the issues you find during your
audit.

From there we're going to go
beyond the basics to look at
some of our more advanced APIs
to help you solve some common
problems that you might find
while making your own apps
accessible.
And finally, I'd like to spend a
little bit of time talking about
some accessibility
considerations that you should
make when implementing the
drag-and-drop in iOS 11.
So, let's get started.
The first feature I'd like to
talk about today is text
detection.
So, let's imagine for a second
that you're a VoiceOver user
who's blind and you're scrolling
through your favorite social
media app and you come across an
image like this where somebody
has embedded text within an
image.
When you tap on it you're
probably not going to hear a
description of what's actually
in the image unless the
developer has gone through and
done the work to put a label
that describes it to you.
But this year in iOS 11, as well
as on macOS if you focus on an
image we're going to do some
basic text detection to try and
figure out if there's text
within that image and if it
makes sense to speak it then
we're going to speak to the user
and it sounds a little something
like this.

Possible text, I can't
believe I took this with my
iPhone.

Now along that same vein,
we're introducing improved photo
descriptions for VoiceOver users
systemwide.
So, when a VoiceOver user
focuses on an image we're going
to run some basic analysis to
try and figure out what's
contained within that image and
speak details about it so that
VoiceOver users get a richer
description.

We look for things like the
number of faces within an image,
what expressions are they
making, what's the overall scene
of that image, and what's its
blurriness or brightness level.

So, a description for an image
like this one might sound like
this.

One face, one smiling,
nightclub, blurry, bright.
Now if you're a developer
who's already gone through and
done your due diligence of
labeling all your images don't
worry we're not just going to
hijack that description from
you.

Instead, if a user wants to hear
the description that we
ourselves have generated that
all they need to do is a single
three-finger tap on the image
and they'll hear our
description.
Next, we have large texts.
So, this year our team did an
audit of the large text
experience systemwide with a
real focus on the experience of
those users who use our largest
accessibility text sizes.
And we worked with teams across
Apple to really, really improve
this experience, which also
includes some new APIs.

Now there's a lot that I could
say about this feature.
In fact, there's so much that I
could say about this feature
there's a whole other session
dedicated just to dynamic type
it's called Building Apps with
Dynamic Type.
It's going to be in the
executive ballroom Friday at
1:50 and I highly, highly
recommend that you attend to
figure out how to best adapt
your own apps for dynamic type
in iOS 11.

Now there are two other sessions
up here that I'd like to point
out that also contain relevant
information about dynamic type.
The first Design for Everyone is
a session that focuses on the
design of accessibility, but
will also contain a portion that
will cover dynamic type,
including some of the rationale
behind decisions that we made
when adapting the layouts for
large text and design
considerations that you yourself
should make when designing your
own apps.
And second, Auto Layout
Techniques in Interface Builder
will have a portion dedicated to
adapting your layouts that are
built with interface builder for
dynamic type.
So, I hope to see you all at
these sessions.

Moving on, we have the
Accessibility keyboard.
This is a feature built for
macOS for users who have enough
dexterity to use a trackpad, but
can't necessarily use a physical
keyboard.
It's an onscreen keyboard that
has things like system controls
and a predictive text bar and is
fully customizable, which means
that if I have certain actions
that I do on a daily basis that
I want to create a custom panel
for so I just have to click it
once and it'll initiate that
action then I can create those
panels.

So, for instance if I email my
manager every day I may create a
custom panel that opens mail,
composes an email, and adds her
address in there.
Next, we have Type to Siri, so
like the title suggests this
feature allows you to interact
with Siri via text input like
you would via speech.
And we're really excited about
this because it's going to open
up Siri to a class of users who
are unable to use it before,
those who are nonverbal.

Finally, we have Smart Invert
Colors.
So, previously on iOS if you
enabled the invert colors
feature it would invert all the
content of your device
regardless of what kind of
content it is.
But this year we're introducing
Smart Invert Colors, which looks
at specific kinds of content
like graphics or images and
doesn't invert them so that you
can see the content as it was
actually meant to be.

Now as you can see, the
wallpaper wasn't inverted nor
were all of the app icons.

And if I go into my Photos app,
you'll see that I still have the
dark UI that is important for
users who use invert colors that
have certain low-vision
conditions where a white UI
makes the display too difficult
to look at for prolonged periods
of time.

So, I can still see my photos as
they originally were.
Now if I go to an app like Clock
which already had a dark UI
you'll also notice that we
haven't inverted that UI to keep
the dark look around that is so
important to our invert colors
users.

Now that's just a very basic
overview of that feature and I
highly recommend that you check
it out yourself and see how it
plays around with your own apps.
But now I'd like to pivot into
talking about the experience of
you as a developer and how you
make sure that all of your work
works with all the things that I
just covered, as well as all of
our old features.

And that really begins by
auditing your app for
accessibility.

So, when we're starting an audit
the first thing you're going to
want to do is enable an
accessible technology like
Voiceover or Switch Control and
see what the experience is like
for a Voiceover user.
So, to do that we're going to
tap on General Accessibility and
go down to this accessibility
shortcut page and add VoiceOver
to our shortcut.

What this does is that now
whenever I triple click the Home
button VoiceOver will turn on
and if I have VoiceOver on
already it will turn VoiceOver
off so I can quickly cycle
between the two as I'm going
through my app.
And now that we have VoiceOver
on.
We're going to Home out of
settings and go to the app that
we want to audit and just start
playing around to see what the
experience is like for a
VoiceOver user.
Are all the things that I would
expect to be visible visible?
Are the things that I would not
want to be visible to a
VoiceOver user not visible to
them?
Does every interaction with the
interface have some sort of
corollary that a VoiceOver user
can take advantage of?
And does the UI itself make
sense, does the flow make sense?
As well are elements properly
labeled?
For instance, I would expect
this button that's an upload
button to be labeled upload tell
me it has three votes currently
and that it's a button.
Now we have a tool called the
Accessibility Inspector that can
also be used for auditing your
apps.

You can get to it by going to
Xcode, open Developer Tool and
opening the Accessibility
Inspector.
And what this tool allows you to
do is look at specific elements
of your screen and get their
accessibility information, as
well as run a full audit of the
accessibility in your app.
Now I'm not going to cover using
this tool today, but there was a
session at last year's WWDC that
covered extensively how you take
advantage of this app and work
it into your own workflow.
So, if you're interested in that
I recommend that you check it
out at this link.
Instead, what I like to do now
for you is demo auditing a
sample app that I've been
working on.
So, I'm going to come to my
device here and you can see I
have this app down in the corner
called Pre-Poster.

Now this is an app I've been
working on that allows me to
post posts to a social network
to a close group of friends
before I post it to the wider
social network to make sure I
have all my friends' approval of
those things I'm posting.
Now I have things like up vote
buttons and down vote buttons so
that friends can tell me whether
it's good or not, comments, I
have even star ratings so that I
can rate how good a post is, and
I have settings that allow me to
set which social networks I want
to automatically post to when
the timer runs down.

So, let's turn on VoiceOver and
just see what we find.
I'm going to triple click the
Home button and as you can see,
I have my accessibility
shortcuts to include the
VoiceOver and Smart Invert and
I'm going to select VoiceOver.
VoiceOver on Pre-Poster Tom
McNeil, [inaudible] button,
three button, button, two open
posts.

So, I'm swiping my finger
with VoiceOver to navigate
between elements onscreen and I
noticed a couple of things
there.
First of all, elements were out
of order.
I swiped from one label to the
buttons to the second label.

Both labels didn't give me any
indication that I can actually
tap on them to go into my own
profile and see all my own
posts.
And all of those buttons were
missing labels to tell me what
they actually do and what
they're meant to be.

So, let's keep going.
Lexi Torres five minutes
remaining, just finished my set
three comments, two button,
three button.
Now those two buttons have
their values because I'm storing
the number of votes in the
buttons text label so VoiceOver
is able to read that, but again
they're unlabeled because I have
no idea what those buttons
actually do, what is the three
ore the two associated with.
I'm going to come down here and
I'm going to try and focus on
the star view.
What you're hearing is VoiceOver
indicating to the user that
there's no accessible element
underneath my finger.

And that means that the star
view is not accessible at all so
we're going to need to fix that.

Button.
Let's check out the settings
page.

Settings close button.
That seems to be labeled
properly.

Facebook, Facebook.
So, two things I notice here.
First of all, the cell isn't
indicating to me whether or not
the setting is actually enabled.
And secondly, when I did a
double tap to activate it I
would expect it to enable or
disable the setting and that
didn't happen either.
Close.
Now one other thing I
noticed.
Tom McNeil.
Is that when I was swiping
through items on my post it gave
me no indication that I can
actually delete the post.

When I'm not using VoiceOver if
I do a long press on one of
these cells it brings up an
action sheet to initiate a
delete.
But that interaction isn't clear
to a VoiceOver user at all and
they have no way of initiating
it.

Alert accessibility short
VoiceOver off.
So, let's take a look at some
of the basics of our API to
solve these problems.
Just to recap, this is what we
found.
First, we had elements that were
out of order and my profile
elements didn't indicate that I
could tap on them to get to my
own profile so it really makes
sense to group them together as
a single element that acts as a
button.

Next, I have unlabeled buttons
on the top, as well as these on
the cell.

The star view was entirely
inaccessible, as was initiating
a delete of a post.

And finally, the settings didn't
tell me whether or not they were
enabled and an activate of them
didn't actually change the
value.
So, how do we solve them?
Well when a technology like
VoiceOver is trying to get
information about an element for
an app, so when a VoiceOver user
focuses on an element on the
screen it's going to ask a
couple of questions.
Questions like what are you, I'm
a button?
Who are you, I'm a Notifications
button?
What's your value, three unread
notifications?
Now all of these questions and
answers correspond to properties
in code and return specific
kinds of return values.
So, let's take a look at this.

Here we have the five basic
properties in the accessibility
protocol and we're going to go
through them one by one looking
at an example.
So, the first
isAccessibilityElement indicates
to a technology like VoiceOver
or Switch Control whether the
given element should be visible
to VoiceOver at all.
So, if we're looking at the
memory view up in the corner
there that has a slideshow of
images within the memory, a
label with the title, as well as
a play button that's a great
candidate for making a button,
the overall element a button
that when I tap on plays the
movie.

So, I'm going to set
isAccessibilityElement to be
true on that memory view.

But now because of the way that
I've coded this it's possible
that this play button is still
going to come up as an
accessible element to VoiceOver
and because I'm making that
overall element the target
instead then I want to set this
play button's is excessively
element to be false so that it
doesn't come up and we don't
have redundancy there.

And one thing that I forgot to
mention is that it's a good idea
to make the big area the play
button instead because if I'm a
VoiceOver user navigating around
this UI with by just feeling my
finger around the screen it's
much harder to find that tiny
play button to play the movie
than it is to find that big
area.
Next, we have accessibilityLabel
which describes what an element
is.
So, for example with our memory
view it's a memory and its title
is February 18th, 2017.
So, that seems like a reasonable
label.
But now because we're going to
be treating it like a button you
might wonder why we don't add
the word button into our label
and that's because of this next
property, accessibilityTraits.
This indicates to VoiceOver what
category an element fits into.

So, for example we're going to
set our memory view
accessibilityTraits to include
the button trait so that
VoiceOver knows to treat it like
a button.

This also means that when it
reads the description for the
item it's going to say button at
the end of that so that the user
knows what it is.
Now traits are also important
for two more reasons.
One, they can afford certain UI
behaviors which you'll see you
later in the presentation.
And two, there's mechanisms for
users to navigate the interface
based on specific kinds of items
that will be surfaced based on
what traits are associated with
it.
Next, we have accessibilityValue
which is for elements that have
some form of state.
So, for instance if we're in our
memory video and we're editing
there's a scrubber along the
bottom that allows me to scrub
through the whole video.

And the current valve of that
item is the second that I'm
focused on of the elapsed
seconds that have already
happened.
So, I can set its accessibility
value to be that elapsed number
of seconds that I'm currently
looking at.

Finally, we have
accessibilityHint.
Now this is meant to be a more
longform description of how to
interact with an element, what
it does or what it's meant for.

You can think of this as being a
property that allows you to
describe to a user that's new to
your interface and help them
learn how to use your interface.
But it's important that you
never put critical information
to whoever's using it in a hint
because hints can actually be
disabled to keep VoiceOver from
being too verbose for
experienced users.

So, going a little further.
New this year we have attributed
versions of label, value and
hint.
And what these allow you to do
is pass through specific keys to
tweak the way in which VoiceOver
speaks a string.
So, for example if I have a
string that I know I want to
speak -- that's in a different
language and should be spoken
with a different voice
synthesizer specific to that
language then I can use the
UIAccessibilitySpeech
AttributeLanguage key and pass
in the correct language code so
that when VoiceOver speaks it,
it speaks it with say in this
example, the French synthesizer.

Now as well let's say I had an
announcement that I wanted to
post and speak, but I felt like
that announcement isn't
important enough to interrupt
whatever current speech is
happening.
Well in this case I can use an
attributed string with the
UIAccessibilitySpeech
AttributeQueueAnnouncement that
will queue the speech behind
whatever existing speech is
already there so that it will be
spoken whatever VoiceOver was
already speaking is done.
Also, new this year we have the
concept of containers.

So previously, when a VoiceOver
user would swipe into a
container of some kind they
wouldn't really get an
indication of what kind of thing
they were swiping into, what
does those content actually even
mean.
So, we're introducing
accessibilityContainerType where
you can define this and there
are several different kinds of
containers.
The biggest one there is
dataTable which actually
requires conformance to the UI
accessibility container
dataTable protocol and improves
the way in which a VoiceOver
user can navigate through your
dataTable and understand where
they are.
So, everything that I just
covered there applies to views
that you would use through UIKit
you.
But what if your controls exist
out of UIKit, you have some sort
of non-view element that perhaps
you've drawn using core
graphics.
Well in that case we still need
to surface those controls to
VoiceOver and so we're going to
use UI accessibilityElement to
represent logical accessible
regions of the screen to
basically stand in for those
controls.

So, UI accessibilityElement you
set all the properties that I
covered before on it like you
would on any other view and it's
initialized with an
accessibility container that
would be the view that it's
contained in.
And then you override on the
container the
accessibilityElements protocol
which tells VoiceOver what sub
elements within a view are the
accessible elements.
And the order in which elements
are returned in this array is
the order in which VoiceOver
will swipe through them.

So that seems like a great
candidate for combining those
profile elements into a single
element.
So, let's come back over to our
sample app and take a look at
implementing some of these
basics.
Okay, so I have -- I'm in my
home view controller which is
the main screen I'm on and the
first I want to do is fix the
labels for those buttons that
are up on the top.
So, for the add button I'm going
to say new post because it
creates a new post.
The notifications button I'm
going to set its label to be
notifications and its value to
be my current number of unread
notifications.
And then the settings button I'm
going to set to be settings.

Now I'm going to go take care of
those other unlabeled buttons
that were my upload and download
buttons.
So, for my approved button I'm
going to set its label to be up
vote and for my disapprove
button down vote.
Now I need to also remember to
change the accessibility value
of these buttons whenever my
number of approves or number of
disapproves changes.
So, when I come into here I'm
going to make a switch statement
based on number of approves.
When it's one I'm going to say
it's the number of approves vote
or when it's more than one I'm
going to day number of approves
votes.

And I'm going to do the same
thing.
For the disapprove.

So, let's go to the star view
which was previously
inaccessible and we're going to
make that an accessible element.
The first thing that we're going
to do is override
isAccessibilityElement to return
true so that VoiceOver knows
that this is an element it
should focus on.
Going to set its label to be
star rating because that's what
it is.
And then for its value based on
the number of stars we're going
to return either no rating, one
star or the current number of
stars.

So now let's come back to the
home view controller where we
had those labels that we wanted
to join together to be a single
element that acted like a
button.

So, what we're going to do for
that is a couple things.
We're going to create a UI
accessibilityElement the
container of which is the header
view and then we're going to set
its label to be my profile name,
its value to be my number of
open posts, and its traits to
include the button traits so the
user knows that they can
interact with it like a button.

And then I'm going to find its
frame and set this property
accessibilityFrame
InContainerSpace.
Now this is important because
for a couple reasons.

It's telling VoiceOver where the
element is onscreen and the
coordinate space of its
container which is used to draw
the bounding box, as well as
when a VoiceOver user is feeling
around the screen for elements
it's using this property to
detect whether or not an element
can be found underneath their
finger.
Finally, on our header view,
we're going to set our
accessibilityElements to contain
our new element plus those three
buttons that we had already.
Last but not least, I want to
come to the switch cell and make
this the whole cell an
accessibility element and for
its value based on whether or
not the switch is currently on
I'm going to say on or off as
its accessibility value.

Alert, selected.
Okay well I have thankfully a
premade version of this that
actually already has the
accessibility in it so we're
going to launch that and I'm
going to turn on VoiceOver.
VoiceOver on Pre-Poster EX
Tom McNeil two open posts
button.
And the first thing that you
see is that I have joined those
elements together and that it's
spoken that it's a button.
Tap the add button,
notifications three, button
settings button.
All those buttons have proper
labels.
Down vote two button, up vote
three button.

Those have proper labels as
well.
Page two of four star rating,
no rating, adjustable.
I can focus on the star, sorry.
I can focus on the star rating
view, it's actually a view now.
If I go into my settings.
Settings, setting, Facebook
off.
I'm finally actually reading
whether or not my setting is
currently off or on.
Now there are a couple of
problems that we found during
our audit that we still haven't
actually fixed.
I still have no way of bringing
up the delete sheet.
I have no way of actually
changing the value of the star
rating view.
I can see what it is, I can see
what the current number stars
is, but I have no way of
changing it.
And when I double tap on my
setting it's still not changing
that setting value.
So, the first thing I want to
look at are custom actions.
So, we're going to use these to
bring up that delete sheet in
our sample app.
Basically, a custom action is
something that you add to an
element that is an action that
it has available to it.
So, views have the property
accessibilityCustomActions which
you can override with an array
of UI accessibilityCustomAction
that are all of the actions
available to it.
So, what does an action look
like?
Well it has a name for instance,
our delete action is called
delete because it tells the user
what it does and it has a target
and a selector that get called
whenever that action is
initiated.
So, when a view has custom
actions it's going to tell that
to the user and then the user
can swipe up or down with their
finger to cycle through the
current actions of that element.
And when they land on the one
that they want to activate a
double tap instead of doing
whatever the default behavior
will do will initiate that
action.
So, for instance, with our
delete we can create a custom
action called delete, set our
self as the target with our
delete cell action method that
returns a Boolean and that calls
the code for actually initiating
the delete of the cell.
On our cell, we're going to
override
accessibilityCustomActions to
contain this custom action.
Now because we're overriding it
on the cell and the cell itself
isn't an accessibilityElement,
all of its sub elements are.

All of its sub elements are
going to inherit the custom
actions of its parent.

So, I can actually initiate this
delete action from any of the
views on the cell.

Next, we have the default
activation.
So, what if we want to actually
override what the default
behavior is when a VoiceOver
user double taps on an element.

And that's what we're going to
use to fix the problem of
actually changing our settings.

What you can do is override
accessibilityActivate, which
returns a Boolean indicating
whether or not the activation
was successful.
So, for example with our switch
cells we can override
accessibilityActivate and set
whether or not the switch is on
based on its current on value.
And we're always going to return
true because we know that that
action is always going to be
successful.
Next, we have adjustable
elements, so our star rating is
adjustable and VoiceOver has a
mechanism for adjustable
elements to respond to increment
and decrement calls.
So, the first thing we want to
return in that element's traits
that it is an adjustable element
and that tells VoiceOver that
element is going to respond to
the accessibilityIncrement and
decrement calls which we can
override to do whatever behavior
we need when we increment and
decrement.

And a user adjusts an adjustable
element by swiping up and down
with their finger.

Up as an increment, down as a
decrement.
So, with our star's view we have
the number of stars that
whenever it's set has code that
actually adjusts the view
itself.
In its traits, we're going to
include the adjustable trait.

And in increment we're simply
going to increase the number of
stars by one and in decrement
we're going to decrease the
number of stars by one and now
that element is fully accessible
to our VoiceOver users.
Now I'd like to look at a
different problem that we didn't
see in our sample app.
So, VoiceOver has this concept
of pass-through which happens
when a VoiceOver user double
taps and holds their finger and
it passes through the panning
gesture so I can actually run my
finger across the screen and get
a more fine adjustment of a
slider like you see in this
photo's page here.
But we want a way to tell
VoiceOver where it should
actually focus that panning when
I initiate it because if I'm a
VoiceOver user then I probably
am not going to be able to
accurately land my finger on
that little sliding nub in the
center right, I don't actually
know where it is.

So, we're going to use
accessibilityActivationPoint
which is the point that tells
VoiceOver when a pass-through
occurs, what part of the UI do
you actually want to hook into.

So, for instance, if we have our
slider view where we have some
sort of slider nub then we can
override
accessibilityActivationPoint to
be the center of that nub so
that whenever the user passes
through that gesture it will
hook into the center of the nub
and start sliding there.
Next, we have custom scrolling,
so you may have views that have
swipe gestures on them that you
can use to get to different
parts of the UI.

For instance, in photos if I
swipe up then I get to my
details.

And there's a way that we can
get this behavior for VoiceOver
users as well.

It's called an
accessibilityScroll, it's
initiated by scrolling with
three fingers when VoiceOver is
on.
And it returns a Boolean to
indicate whether or not the
scroll was successful.
And it passes through a
direction so that you can change
the behavior based on what
direction the user is scrolling.

So, for example with our image
view if we wanted to show
details like we do in the Photos
app we'd have some property that
tells us whether or not we can
currently show the details and
we have code that actually goes
through and shows those details.
And so, what we're going to do
is override accessibilityScroll,
we're going to check can we show
our details and are we scrolling
in the right position or
direction.
And if we do we're going to show
our details and return true,
otherwise we're going to return
false.

And when I return false
VoiceOver is going to make a
bonking noise to indicate to the
user that whatever swipe that
they just did was not a valid
swipe.

Now I'm not going to go through
actually adding all those things
into our sample app, but they
are in the finished version of
the sample which you can find
and download at this URL.

And I recommend that you go and
check it out and see how that
code is implemented and see how
it works in action, play around
with it yourself.
Instead, I'd like to spend a
little bit of time talking about
Drag-and-Drop.
So, for those of you that missed
it at the keynote we unveiled
Drag-and-Drop finally coming to
iOS where I can drag pieces of
content and drop it in other
places in the interface.
For instance, if I have photos
open next to notes I can drag a
photo and drop it into one of my
notes.

Now because this was just
unveiled two days ago I don't
really expect all of you to
already understand how that API
works.
But there are just two key
concepts that you need to
understand before I talk about
the accessibility and that's
drag sources and drop points.
So, drag sources are all the
points on my view that I can
initiate a drag from and drop
points conversely are all the
places on my view that I can
drop content.
So, for instance, on the Home
screen which now uses
Drag-and-Drop for rearranging
icons I have three drop points
for each app when I'm moving
another.
The first is the left drop point
which allows me to drop the app
I'm currently moving to the left
and shift everything else to the
right.

I have the center drop point
that will create a folder
between the two apps.

And I have the right drop point
that will drop my current app to
the right.

And we need a way of describing
those different drag sources and
drop points to our VoiceOver
users.
And to do that we're going to
use this new API
accessibilityDrag
SourcesDescriptors and
accessibilityDrop
PointDescriptors.
They're arrays of
UIAccessibility
LocationDescriptor that
described the drags and the
drops for review.

So, we create a UIAccessibility
LocationDescriptor for each
drag-and-drop.

The view is going to be the view
that has the drag or drop
interaction associated with it.

The point is the point where the
drag is initiated from or the
drop is associated with.

And the name is meant to
describe what that drag or drop
does.

And there's even an attributed
name where you can use all those
attributed keys that I was
referring to earlier to tweak
the way that VoiceOver describes
the name of the descriptor.

So, let's take a look at how
this works in code.
Now this is just a hypothetical
example this isn't an actually
springboard code.
But let's say that I was
implementing rearranging apps
and I have a method that returns
an app view for a given index
path.
Well I'm going to start by
initializing that app view and
then I'm going to create a drag
descriptor and I'm going to give
it the name drag whatever the
app name is because that's what
I'm doing.
And then the center of where the
app is dragged from or sorry the
point where the app is dragged
from is its center.

And the view that actually has
that drag interaction is myself.
Then I'm going to override the
app view's drag source
descriptors to include that new
drag descriptor.

Now let's look at the drops.
So, first of all, we need to
identify the points on my app
view where I actually want to
use the drop, the left and the
right point, I know where the
center is already.
And I'm going to create a
descriptor for each of those.

My leftDescriptor I'm going to
say drop left of blank,
folderDescriptor I'm going to
say create a folder with the app
and the rightDescriptor drop
right of the app.

And then I'm going to override
accessibilityDrop
PointDescriptors to include all
those new descriptors and I'll
return my app view.
And that's it, pretty simple.

But important to convey for the
VoiceOver user what each of your
Drag-and-Drop interactions are
like.
So, if you're going to implement
this feature then please take
the time to do the accessibility
for it as well.
Now I talked about a lot of
stuff today, we looked at some
new features, we looked at
auditing your own app for
accessibility, and we looked at
various portions of our API to
solve the problems that you find
while auditing.
And that's all great technical
stuff, but I want to bring it
back to the beginning to remind
you why we're all actually in
this room.

Accessibility is about people,
the common person's life is
enhanced by technology, but for
people with disabilities it's
transformative.
Accessible technology enables
people to live their lives the
way that they want to, to
accomplish goals and tasks that
were once unattainable, to have
jobs and roles in their
communities that they couldn't
have had before, and to interact
with the world in ways that were
once impossible.

The work that you do to ensure
that your apps work for everyone
is critical.

So, we thank you for the amazing
work that you've already done,
that you will continue to do,
and that you will start today as
we work together to make Apple's
platforms more inclusive.

Now for more information, you
can go to this URL where we've
collected some URLs that are
helpful for you like some
developer documentation, as well
as our accessibility website.

And there are a couple of
related sessions, there are the
three sessions related to
dynamic type that I covered
before, and there's a media and
gaming accessibility talk
specifically for apps related to
media and gaming that's in this
room right after I'm done.

Thank you very much, have a
great rest of your conference.

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